1. Field of the Invention
The present invention relates generally to an automatic following device, and more particularly to an automatic following device that automatically follows a desired subject by changing a shooting condition such as a shooting direction of a camera.
2. Description of Related Art
An automatic following device automatically changes a shooting direction of a camera mounted on a pan head by panning and tilting the camera with motors to follow a moving subject. Japanese Patent Publication No. 6-14698 discloses an automatic following method in which a differential image between two images with a predetermined time interval is acquired in order to abstract an moving subject, and a moving amount and a moving direction of the subject are determined from a center position of the subject. Then, the shooting direction of the camera is automatically changed by a pan head according to the determined moving amount and moving direction of the subject so that the moving subject is the center of a frame of the camera.
In the above-described method, however, since the camera is panned and tilted so that the subject is the center of the frame, the camera is panned and tilted when the subject moves even a little in the frame, and thus the image is blurred.
Also, in case a person is followed as the subject, the head of the person is in the upper part of the frame, and the head can be out of the frame. The above-described method is not always desirable when a specific part of the subject is shot while the subject is followed.
In addition, in case there are a plurality of moving subjects in the frame, the appropriate subject to be followed can not be determined, and the desired subject can not be appropriately followed.
It is therefore an object of the present invention to provide an automatic following device that can follow a subject while minimizing an operation of a camera to obtain an image that is not blurred.
It is therefore an object of the present invention to provide an automatic following device that can follow a subject while shooting a specific part other than a center position of the subject.
It is therefore an object of the present invention to provide an automatic following device that can follow only a desired subject even if there are a plurality of moving subjects in a frame of a camera.
The above object can be achieved by providing an automatic following device that follows a subject by changing a shooting condition that is at least one of a shooting direction and a view angle of a camera, the automatic following device comprising: a shooting registering device that previously registers one or more shootings by setting shooting conditions of the camera; a position determining device that determines a position of the subject; and a shooting changing device that changes one of the shootings to another registered by the shooting registering device according to the position of the subject determined by the position determining device so that the subject is in a frame of the camera.
According to the present invention, the shooting is switched only to another registered shooting according to the position of the subject to be followed so that the subject is the center of the frame. Thus, the shooting condition does not change even if the subject to be followed moves a little within the field of view. Therefore, the image shot by the camera is not blurred. Also, since the desired zooming position as well as the panning position and the tilting position can be stored as the shooting conditions, the shooting is performed with the appropriate view angle according to the panning position and the tilting position.
The above object can be achieved by providing an automatic following device that follows a subject by changing a shooting direction of a camera, the automatic following device comprising: a position determining device that determines a position of the subject; a determining device that determines whether or not the subject is in an insensitive area set in a frame of the camera; and a controlling device that does not change the shooting direction when the determining device determines that the subject is in the insensitive area and changes the shooting direction to follow the subject when the determining device determines that the subject is out of the insensitive area.
According to the present invention, the insensitive area is set in the frame, and only when the center position is out of the insensitive area, the camera is turned to shoot the subject. Thus, the shooting direction of the camera does not change even if the subject moves a little in the frame, and therefore the image is not blurred.
The range of the insensitive area is determined according to the position of the subject to be followed. For example, the farther the subject is from the center of the frame, the smaller the range of the insensitive area is. Therefore, the subject never goes out of the frame to be followed.
The above object can be achieved by providing an automatic following device that follows a subject by changing a shooting direction of a camera, the automatic following device comprising a controlling device that changes the shooting direction so that a specific part other than a center position of the subject is in a frame of the camera.
The controlling device changes the shooting direction so that the specific part of the subject is the center of the frame of the camera.
The controlling device determines the specific part of the subject so that an area ratio of one side of the subject divided along a vertical line with the specific part to the other side is a predetermined value and changes the shooting direction so that the specific part is on a vertical line with the center of the frame.
The controlling device determines the specific part of the subject so that an area ratio of one side of the subject divided along a horizontal line with the specific part to the other side is a predetermined value and changes the shooting direction so that the specific part is on a horizontal line with the center of the frame.
According to the present invention, the subject can be followed while its specific part that is different from its center position is in the frame. For example, when the person is followed, the head of the person is in the frame.
The above object can be achieved by providing an automatic following device that follows a subject by changing a shooting direction of a camera, the automatic following device comprising: a hue setting device that sets a hue of the subject to be followed; a moving subject abstracting device that abstracts moving subjects from images captured by the camera; a subject choosing device that chooses the subject to be followed among the moving subjects abstracted by the moving subject abstracting device according to the hue set by the hue setting device; and a controlling device that changes the shooting direction according to a position of the subject chosen by the subject choosing device.
According to the present invention, the subject to be followed is determined by the hue. Thus, only the subject can be appropriately followed even if there are a plurality of moving subjects in the frame.